1251601501 has 4 divisors (see below), whose sum is σ = 1257115392. Its totient is φ = 1246087612.

The previous prime is 1251601499. The next prime is 1251601537. The reversal of 1251601501 is 1051061521.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1051061521 = 23 ⋅45698327.

It is a cyclic number.

It is not a de Polignac number, because 1251601501 - 2¹ = 1251601499 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251601541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2756605 + ... + 2757058.

It is an arithmetic number, because the mean of its divisors is an integer number (314278848).

Almost surely, 2^1251601501 is an apocalyptic number.

It is an amenable number.

1251601501 is a deficient number, since it is larger than the sum of its proper divisors (5513891).

1251601501 is an equidigital number, since it uses as much as digits as its factorization.

1251601501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5513890.

The product of its (nonzero) digits is 300, while the sum is 22.

The square root of 1251601501 is about 35377.9804539490. The cubic root of 1251601501 is about 1077.6771925942.

The spelling of 1251601501 in words is "one billion, two hundred fifty-one million, six hundred one thousand, five hundred one".